On preparing Ox-Gall for Painters, &c. 3013 
Directions respecting Grounds. 
No, 1.—The ground in hot weather must have an addi- 
tional one-third of spirits of wine added to it for coarse 
grounds, to represent chalk ; and one-half added to it for 
fine grounds, to represent black-lead pencil; and always to 
be kept in a cold place in summer, and a moderate warm 
Situation in winter. 
N. B.—If any parts are not bit strong enough, the same 
process is to be repeated. 
Gum-water must be made in the proportion of half an 
ounce of gum-arahic to a quarter of a pint of water. 
Turpentine-varnish is composed of an ounce of black 
rosin to an eighth part of a pint of spirits of turpentine: if 
the weather is excessively warm, it ought to be made with 
a sixth part of a pint of spirits of turpentine. 
Tracing-rag should be made of a piece of Irish linen, 
not too much worn, the surface of which is to be rubbed 
with another rag dipped in sweet oil, just sufficient to retain 
asmall portion of vermilion or pounded red chalk. This 
must be placed with the coloured part towards the ground, 
of the plate, and the drawing or tracing laid upon it, which 
must be traced very lightly with a blunt point or needle. 
LI. Method of preparing Ox-Gall in a concentrated State 
Sor Painters, and for other Uses. By Mr. Ricuarp 
Catuery, of Mead’s Row, Westminster Road *. 
I; has been long a desideratum to find out a method of 
preparing ox-gall for the use of painters, so as to avoid the 
disagreeable smell which it contracts by keeping in a liquid 
state, and at the same time to preserve its useful properties. 
I have invented a method of doing it with very little ex- 
" pense, which will be to those who use gall a. great saying, 
as it will prevent it from putrefying or breeding maggots. 
One gall prepared in my method will serve an artist a 
long time, as it will keep a great number of years. It will 
be a convenient article for use, as a small cup of it may be 
laced in the same box which contains other colours, where 
it will be always ready. The qualities of gall are well 
known to artists in water-colours, particularly to those 
* From Transactions of the Society for the Encouragement of Aris, Maxu- 
factires, and Commerce, vol, xxviiii——The Society voted ten guineas to» 
Mr, Cathery for this communication. 
who 
